Evaluation of the impact of COPD severity grading and oxygen saturation on the retinal nerve fiber layer thickness and subfoveal choroidal thickness in COPD patients

Table 2 Correlation between the GOLD classification of COPD patients and the studied eye parameters

		GOLD I	GOLD II	GOLD III	GOLD IV	Test value	P value
Superior RNFL μm	Mean ± SD	113.38 ± 11.31	99.42 11.79	96.40 14.79	69.08 ± 10.27	29.025	0.001
Superior RNFL μm	Range	93–126	64–121	79–120	58–90	29.025	0.001
Inferior RNFL μm	Mean ± SD	112.75 ± 9.90	100.58 5.93	102.60 1.52	78.38 ± 16.53	22.301	0.001
Inferior RNFL μm	Range	96–131	90–115	101–104	55–104	22.301	0.001
Nasal RNFL μm	Mean ± SD	59.75 ± 8.36	67.38 ± 11.92	60.20 ± 3.96	63.00 ± 12.12	1.370	0.264
Nasal RNFL μm	Range	53–75	55–98	57–65	40–80	1.370	0.264
Temporal RNFL μm	Mean ± SD	70.8 8 ± 4.55	68.29 ± 12.81	53.00 ± 1.41	45.69 ± 5.3	19.444	0.001
Temporal RNFL μm	Range	68–81	51–93	51–54	40–54	19.444	0.001
Average total thickness of RNFL μm	Mean ± SD	89.38 ± 3.38	84.04 ± 4.91	78.20 ± 3.63	64.23 ± 5.72	61.177	0.001
Average total thickness of RNFL μm	Range	85–94	74–98	74–84	58–74	61.177	0.001
SFCT μm	Mean ± SD	241.88 ± 2.30	224.88 ± 5.42	207.80 ± 5.12	175.77 ± 16.08	110.323	0.001
SFCT μm	Range	239–245	218–238	200–214	130–190	110.323	0.001

COPD chronic obstructive pulmonary diseases, GOLD Global Initiative for Chronic Obstructive Lung Disease, FEV₁ forced expiratory volume in the first second, RNFL retinal nerve fiber layer, SFCT subfoveal choroidal thickness